Abstract

The possibility of generating ultrashort optical pulses from narrow‐linewidth lasers by means of mode locking is discussed. An experiment using a He‐Ne 3.39‐μm laser and applying strong intracavity phase (FM) modulation of 580 MHz was performed to demonstrate the possibility. The oscillation bandwidth was observed to be increased over a frequency range of 7 GHz. The pulsewidth estimated from the power spectrum was about 170 ps, while the reciprocal of the linewidth was about 3 ns.